Liquids in Carry-on Plan Change in Europe Under Scrutiny

The European Union plans to relax some restrictions on taking liquids in carry-on bags on airplanes on April 29, which has European and American airport officials concerned.

The rule that air passengers can't bring full-size liquid containers in carry-on bags started with a failed terrorist plot by three British citizens in 2006 -- they planned to bomb trans-Atlantic flights using explosives hidden in soft drink bottles. The U.S. and European Union reacted by restricting the amount of liquids passengers can bring to 3 ounces.

After April 29th, passengers in Europe will be allowed to bring liquids such as wine, liquor or perfume purchased in a duty-free shop on their connecting flights through Europe.

Almost two dozen European airports will be participating in the new rules. Passengers must place their liquids in security tamper evident bags and be willing to have their liquids scrutinized by security personnel.

New machines will be used that can scan a liquid to see if it has the proper density and properties.

But is the change safe and ready?

Christopher Bidwell, Airports Council International-North America's vice president for security and facilitation, has voiced concern that the effectiveness of the technologies European airports will use to screen liquids for explosives is unclear, reports the Associated Press.

There are several new technologies that European airports plan to use, Bidwell says, but they've only undergone laboratory tests, and haven't been tested at airports.

There's also the issue that the U.S. hasn't indicated any plans to change its liquids policy.

Without consistant policies, European airlines flying into the U.S. could be in for an operational mess, Ulrich Schulte-Strathaus, secretary general of the Association of European Airlines (AEA), says in a letter to the European Commission, reports Aviation Week.

"We believe that the commission should undertake all necessary steps to align the EU policy with that of the United States on [liquids]," he writes.

The TSA hasn't said yet whether passengers coming from Europe with approved liquids after April 29 will be allowed to board domestic flights within the U.S.

The agency has looked at technology that could eventually allow all passengers to bring liquids back on planes, but that's a few years down the road.